Page 67 - Prehistoric Animals

I-gwa-na-don

Iguanodon

What is a Dinosaur ?
Known as a Dinosaur

Iguanodon (iguana-tooth*), is an ex-
tinct genus of iguanodontian dinosaur. It lived from the Late Ju-
rassic to Early Cretaceous, around 125 million years ago. It
measured around 10 to 13 metres in length and 4 to 5 tonnes in
weight. It was first named by Gideon Mantell in 1825. It was al-
so, in the same year, the second animal on record to be classified
as a dinosaur**.

Iguanodon was a large ornithopod. It had short forelimbs
and long rear limbs, with a large but long tail, tapering to a
point. It had a longish neck with a medium size head. However,
as an herbivore it had a distinct advantage over other like herbi-
vores. Its jaws, lined with large sharp iguana-like teeth, could
chew sideways as well as up and down. It also had cheeks. This
allowed it to bite off mouthfuls of food. Cheekless herbivores
could only nip off small pieces of food, which they had to chew
and swallow at once.

Another peculiar feature of Iguanodon is its hands. A
large cone-shaped spike grew where you’ could possibly expect a
fifth finger to grow. When the first detached spike was un-
earthed, it was thought to be a horn that protruded from its
snout. However, this was soon rectified when the first complete
fossilized skeleton was unearthed in Belgium. Many suggestions
have been put forward as to what use Iguanodon put this spike
too. Some say it used the spike to open fruit or dig roots from the
ground, others say it used it as a weapon, while others claim it
was a combination of both.

Dozens of fossils have been found in many parts of the
world, some in Europe were found grouped together prompting
some to think Iguanodon may have travailed or grouped in
herds. Rear footprints of Iguanodon found embedded in ancient
rock in Europe, have made some to wonder how Iguanodon
moved around. Did it spend more time on its hindlegs, or on all
fours? As an animal, Iguanodon probably acted on instinct and
used its legs instinctively in accordance with the situation or en-
vironment it found itself in.

* A palaeontologist not knowing what kind of fossil he was looking at examined its teeth. He
mistakenly thought they were the teeth of an extinct giant iguana and named the ani-
mal Iguanodon, meaning—“iguana tooth.”
** The first being Megalosaurus